Radar-based fill level measurement device having a security device

ABSTRACT

A radar-based fill level measurement device having a signal generator for the purpose of generating electromagnetic waves, and an antenna for the purpose of emitting the electromagnetic waves into a container, as well as for the purpose of receiving electromagnetic waves reflected out of the container, having a security device for the purpose of verifying the functional capability or improving the measurement quality of the radar-based fill level measurement device, wherein the security device has a reflector and an adjusting device, and is suitably designed to move the reflector between at least a first position, in which it reflects the electromagnetic waves, and a second position, in which it reflects the electromagnetic waves to a reduced degree, and wherein the security device has a drive which acts on the adjusting device.

CROSS REFERENCE TO RELATED APPLICATIONS

This patent application claims priority German Patent Application 102013 214 324.9, filed on Jul. 22, 2013.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

No federal government funds were used in researching or developing thisinvention.

NAMES OF PARTIES TO A JOINT RESEARCH AGREEMENT

Not applicable.

SEQUENCE LISTING INCLUDED AND INCORPORATED BY REFERENCE HEREIN

Not applicable.

BACKGROUND

Field of the Invention

The present invention relates to a radar-based fill level measurementdevice having a security device.

Background of the Invention

The current state of knowledge is as follows.

Radar-based fill level measurement devices having such a security deviceare known in the prior art, for example from U.S. Pat. No. 8,009,085 B2,and have a signal generator for the purpose of producing electromagneticwaves, and an antenna for the purpose of emitting the electromagneticwaves into a container, as well as for the purpose of receivingreflected electromagnetic waves out of the container, wherein thesecurity device is suitably designed to verify the proper functioning ofthe radar-based fill level measurement device. The security devicesdemonstrated in the prior art have a reflector and an adjusting devicefor this purpose, said adjusting device being suitably designed toadjust the reflector at least between a first position in which itreflects the electromagnetic waves, and a second position in which itreflects the electromagnetic waves to a reduced degree.

The radar-based fill level measurement devices known in the prior artare generally used in containers which are generally constructed astanks or silos for the purpose of storing various different materials.Foods, drinks, drugs, or fuels, by way of example, are stored in suchtanks, such that a measurement of the fill level thereof must be carriedout without contact. In the prior art, such contactless fill levelmeasurement techniques are, by way of example, the radar-based filllevel measurement device mentioned above, or an alternativeultrasound-based fill level measurement device. Radar-based fill levelmeasurement devices are widely used due to their measurement precisionand minimal susceptibility to failure.

The radar-based fill level measurement devices known in the prior artare generally installed in the upper region of a tank or silo via aflange, wherein the electronics are arranged outside, and the antenna ofthe radar-based fill level measurement device is arranged inside, of thehousing. The antenna is suitably designed for the purpose oftransmitting electromagnetic waves—meaning particularly a radarsignal—in the direction of the fill material which is stored inside thecontainer, and of receiving electromagnetic waves reflected by thematerial. The fill level inside the container can be determined based onthe time difference between a transmission of the electromagnetic signaland the reception of the reflected electromagnetic signal.

For the purpose of verifying the proper functioning of the radar-basedfill level measurement device, particularly to verify the properfunctioning when the fill level is maximum, the same being relevant tosafety, it is necessary to include a security device which makes itpossible to determine the proper functioning when the fill level is atmaximum. In the prior art, for this purpose, the practice of manuallyplacing a reflector in the beam path of the radar-based fill levelmeasurement device, during a security test, is known, to verify thefunctioning of the measurement device at the desired maximum fill level,even when the container fill level is lower—by bringing the reflector,when the fill level is lower, into the beam path of the radar-based filllevel measurement device, and thereby generating a reflectioncorresponding to the maximum fill level.

In the devices known from the prior art, for this purpose it isnecessary for an operator to manually place the reflector in the beampath of the radar-based fill level measurement device, wherein theoperator must climb onto the container being monitored in order tooperate the reflector. Because monitored containers are typically silosor tanks with heights up to 35 m, this presents a significant risk. Inaddition, it is considered disadvantageous that, for a securityverification, every single container must be visited and the reflectormanually operated.

The problem addressed by the present invention is that of removing thedisadvantages known from the prior art, and of providing an advancedradar-based fill level measurement device which does not have thesedisadvantages.

This problem is addressed by a radar-based fill level measurement devicehaving the features disclosed herein.

BRIEF SUMMARY OF THE INVENTION

In a preferred embodiment, a radar-based fill level measurement devicecomprising a signal generator for the purpose of generatingelectromagnetic waves, and an antenna for the purpose of emitting theelectromagnetic waves into a container, as well as for the purpose ofreceiving electromagnetic waves reflected out of the container, furthercomprising a security device for the purpose of verifying the functionalcapability or improving the measurement quality of the radar-based filllevel measurement device, wherein the security device comprises areflector and an adjusting device, and is suitably designed to move thereflector at least between a first position, in which it reflects theelectromagnetic waves, and a second position, in which it reflects theelectromagnetic waves to a reduced degree, wherein the security devicehas a drive which acts on the adjusting device.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the drive is connected to theelectronics of the radar-based fill level measurement device, and thereflector moves from the second position into the first position uponrequest by the electronics.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the drive is connected to an operatingunit and the reflector moves from the second position into the firstposition upon request by the operating unit.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the security device is designed to bespring-loaded in the first position.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the drive is driven electrically,electromagnetically, or pneumatically.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein, in the second position, a reductiondevice is arranged in such a manner that the reflector is at leastpartially covered as seen in the direction of the beam path.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the reduction device is designed as adiffusor.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the reduction device is constructed ofa material which absorbs the electromagnetic waves.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the reflector in the second position isaccommodated in the reduction device.

The radar-based fill level measurement device of claim 1, wherein thedrive is suitably designed to move the reflector rotationally.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the drive is suitably designed to movethe reflector linearly.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the reflector is arranged in the firstposition substantially perpendicular to the beam path, and in the secondposition substantially parallel to the beam path.

In another preferred embodiment, the radar-based fill level measurementdevice described herein, wherein the drive is suitably controlled tomove the reflector continuously, and preferably permanently.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a line drawing evidencing a radar-based fill level measurementdevice according to the invention.

FIG. 2 is a line drawing evidencing a detailed enlargement of a securitydevice having a reduction device.

FIG. 3 is a line drawing evidencing a second detail enlargement of asecurity device.

FIG. 4 is a line drawing evidencing a third detail enlargement of asecurity device.

FIG. 5 is a line drawing evidencing one implementation of the embodimentin FIG. 3.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a radar-based fill level measurementdevice according to the invention, having a signal generator for thepurpose of generating electromagnetic waves, and an antenna for thepurpose of emitting the electromagnetic waves into a container, as wellas for the purpose of receiving reflected electromagnetic waves from thecontainer, has a security device for the purpose of verifying the properfunctioning of the radar-based fill level measurement device, whereinthe security device has a reflector and an adjusting device which issuitably designed for adjusting the reflector at least between a firstposition in which it reflects the electromagnetic waves, and a secondposition in which it reflects the electromagnetic waves to a reduceddegree, wherein the security device has a drive which acts on theadjusting device.

According to the present invention, a drive is therefore included whichacts on the adjusting device of the reflector arranged in the container,such that an automated and remote-controllable arrangement is createdwhich renders unnecessary the approach of visiting every singlecontainer, and particularly manually operating the security device.Increased operating comfort is established in this manner, and the worksafety of corresponding security tests is decisively improved.

The drive can be connected, by way of example, to electronics of theradar-based fill level measurement device, and the reflector can moveupon request of the electronics from the second position into the firstposition, such that it is possible to create an entirely automatedprocess for verifying the proper functioning of the radar-based filllevel measurement device, particularly at the position of the maximumfill level. In this manner, a regular verification of the properfunctioning at the fill level which is relevant for safety can becarried out, such that increased operational security of the radar-basedfill level measurement device is also achieved. In this way, it is alsopossible to improve the quality of the measurements which are carriedout. By way of example, it is possible for the measurement device toautomatically determine a degree of contamination of the measurementdevice by means of comparing the signal reflected by the reflector withearlier measurement values, in order to initiate maintenance of thesystem or to recommend different maintenance intervals. The parametersin this case can be, by way of example, chronological values, signalamplitudes, signal widths, or proportional values, such as a signal tonoise ratio, for example.

In one alternative embodiment, the drive can be connected to anoperating unit, and the reflector can move from the second position intothe first position upon a request by the operating unit.

This embodiment constitutes a compromise solution wherein increased worksecurity is created and it is possible to initiate a verification of theproper functioning of the radar-based fill level measurement device, byway of example, by remote control from a measuring station.

In one embodiment of the security device, the same has a spring-loadeddesign in a first position, such that the reflector, driven by thedrive, is brought into the first position, and then is brought back intothe second position by the spring loading once the drive force isremoved. In this manner, it is ensured that a normal fill levelmeasurement is possible when the drive fails, for example.

The drive of the security device can have an electric, electromagnetic,or pneumatic design, by way of example. This listing of different driveoptions is merely exemplary, and does not exclude other drive optionswhich can be considered. Electric, electromagnetic, and pneumaticdrives, however, have been very well tested, and can therefore be usedwith low probability of failure, and therefore high reliability.

In one preferred embodiment, a reduction device is arranged in thesecond position in such a manner that the reflector is at leastpartially covered as seen in the direction of the beam path. By means ofsuch a reduction device, which can be designed as a diffusor, by way ofexample, or additionally or alternatively can be made of a materialwhich absorbs electromagnetic waves, a reliable differentiation isenabled between the reflection in the first position and the secondposition. In addition, the reduction device is also preferably designedin such a manner that, in the second position, there is no reflectionwhich correlates with a fill level. This can either be achieved in thatthe reduction device only generates a very diffuse echo as a result of asuitable surface construction, said echo scattering the transmittedelectromagnetic rays, or in that, alternatively or in addition thereto,the reduction device produces such a high damping of the reflection, asa result of the selection of the material, that the reflection likewisecannot be detected as correlating with a fill level.

In one preferred embodiment, the reflector is accommodated in thereduction device in a second position, meaning that it is particularlyentirely surrounded by the reduction device.

By means of a complete enclosure of the reflector by the reductiondevice, it can particularly be ensured that the reflector is protectedin the second position from external influences, and particularly fromdeposits caused by contamination. In this manner, it is possible toachieve increased reliability of the security device, and extendedoperating life.

The drive of the security device can be suitably designed, by way ofexample, to move the reflector by rotation. When the reflector undergoesa rotary movement, a continuous movement can occur, by way of example,wherein the reflector is rotated in a plane perpendicular to the beampath, such that a continuous transition thereby occurs between the firstand the second position.

The electromagnetic drive can be designed as a step motor for thispurpose, by way of example.

In a further embodiment, the drive can also be suitably designed for thepurpose of moving the reflector linearly, wherein the reflector istherefore transitioned from the second position into the first positionby a sliding movement, by way of example.

In a further embodiment, the reflector can be arranged substantiallyperpendicular to the beam path when in the first position, andsubstantially parallel to the beam path when in the second position.Such an embodiment can be achieved, by way of example, in that thereflector executes a hinge movement—meaning a rotation about an axisperpendicular to the beam path, or is arranged on the adjusting deviceby means of an extension with a 45° miter joint, and rotates about thesame.

In both cases—a hinge movement and a rotation about a 45° miterjoint—the reflector can be withdrawn into the adjusting device, in theparallel orientation of the reflector to the beam path, such that it iscompletely removed from the beam path of the antenna.

In one implementation of the invention, the reflector is continuouslymoved into and back out of the beam path of the antenna. Such acontinuous movement can either take place upon request, or permanently,and can be implemented both in configurations with a rotary movement anda linear movement of the reflector. In the case of such a continuousmovement, for example in the case of a rotation in a plane perpendicularto the beam path of the antenna, the reflector is pivoted into the beampath and then pivoted back out. The amplitude of the signal reflected bythe reflector to the antenna in this case is continuously larger, untilit reaches a maximum, and then drops continuously.

In this manner, a change in the amplitude relative to the position ofthe reflector can be analyzed, by way of example, and a momentarymalfunction or a failure of the measurement device which can be expectedat a later point in time can be determined by a comparison with earliermeasurements. It can also be contemplated that operating parameters ofthe measurement device are modified based on the measured amplitudevalues, in order to prevent malfunctions at a later point in time.

A corresponding approach is also possible with a linear movement of thereflector in a plane which is perpendicular to the beam path of theantenna.

When the reflector executes a pivot movement about an axis which isperpendicular to the beam path of the antenna, the reflector istransitioned from a position proceeding from an arrangement which issubstantially parallel to the beam path of the antenna, into a positionwhich is perpendicular to the beam path, and in the process, a reflectorsurface continuously passes through all angles from 180° to 90° withrespect to the beam path.

In this manner, it can likewise be verified whether a momentarymalfunction has occurred, or can be expected in the future. Here aswell, it is possible to modify operating parameters of the measurementdevice based on the measured amplitude values, in order to preventmalfunctions at a later point in time.

DETAILED DESCRIPTION OF THE FIGURES

FIG. 1 shows a first embodiment of a radar-based fill level measurementdevice 1 having a security device 5 for the purpose of verifying theproper functioning of the radar-based fill level measurement device 1 ata specified fill level. The radar-based fill level measurement device 1is connected to a container 4 via a flange 6, wherein the electronics 13of the radar-based fill level measurement device 1 are arranged outside,and an antenna 3 of the radar-based fill level measurement device 1 isarranged inside, the container 4. The electronics 13 have a signalgenerator for the purpose of generating electromagnetic waves in theradar range, which are emitted via the antenna 3 in the direction of afill material arranged in the container 4. The electromagnetic wavesreflected by the fill material are returned to the antenna 3 andreceived by the same, wherein a determination of the fill level in thecontainer 4 can be made via a determination of the travel time.

A security device 5, having a reflector 7 which is able to pivot intothe beam path of the antenna 3 is also arranged on the flange 6, whereinsaid reflector [7] can be actuated via an adjusting device 9 with apassage 9 c for the purpose of fixing the same on the flange 6. Theadjusting device 9 is connected to a drive 11 which is designed in thepresent embodiment as an electric motor. The adjusting device 9 consistsof a guide tube 9 a which is fixed to the flange 6. The guide tube 9 acan have a miter edge 9 b on the outlet opening, for the adjustingdevice 9, for the purpose of minimizing undesired reflections of theradar beam. The drive 11 acts on the adjusting device in such a mannerthat the latter causes the reflector 7 to rotate about a longitudinalaxis of the adjusting device 9, such that the reflector 7 is able tomove between a first position I, in which it is arranged in the beampath of the antenna 3 and reflects the electromagnetic waves, and asecond position II, in which it is pivoted out of the beam path of theantenna 3 and therefore does not reflect the electromagnetic waves, oronly to a reduced degree. The reflector 7 is arranged, at least in thefirst position I, in a plane which is perpendicular to a beam path A ofthe antenna 3, such that electromagnetic waves are directly reflected tothe antenna 3. The reflector 7 can be arranged, by way of example, at afill level which must be verified, particularly a maximum fill level,such that a regular verification of the functional capability of theradar-based fill level measurement device 1 can be carried out at thiscritical fill level.

In the present embodiment, the drive 11 is connected to the electronics13 of the radar-based fill level measurement device 1, and pivots thereflector 7 out of the second position II and into the first position Iupon request by the electronics 13, such that a functions check can becarried out in an automated manner.

Such a functions check can also be initiated, in the present embodiment,manually, for example from a remote control station, or can preferablytake place in regular intervals in an automated manner.

FIG. 2 shows a detail enlargement of a second embodiment of a securitydevice 5, such as can be used in FIG. 1.

In the embodiment illustrated in FIG. 2, the reflector 7 and theadjusting device 9 are designed—as in the embodiment in FIG. 1—in such amanner that a rotation of the reflector 7 is realized about an axisparallel to the beam path A of the antenna 3. In addition to the designin FIG. 1, in the embodiment in FIG. 2, a reduction device 15 isincluded, which is designed as a diffusor. The reduction device 15 isthereby designed with a surface which diffusely reflects electromagneticwaves emitted by the antenna 3 in the direction of the reduction device15, such that the reflector 7 is positioned in the second position II ina region which is shielded by the reduction device 15, such that anadditional reduction of the reflections caused by the reflector 7results. The reduction device 15 can, in addition or as an alternativeto a diffusely reflecting surface, also be constructed of a materialwhich absorbs the electromagnetic waves, such that a further reductionof the amplitude of the diffusely reflected electromagnetic wavesresults.

A further embodiment of a security device 5 is illustrated in FIG. 3,wherein the reflector 7 in this embodiment is designed to be able topivot and/or hinge about an axis 17 which runs perpendicular to the beampath A of the antenna 3. A pivoting and/or hinging in the context of thepresent application means that the reflector 7 is arranged in the firstposition I substantially perpendicular to the beam path A, and in thesecond position II substantially parallel to the same. A transitioningof the reflector 7 from the first position I into the second position IIis realized by a pivoting about an angle of approx. 90°, such that thereflector 7 is arranged in the second position II as an extension of theadjusting device 9. As a result of the fact that the reflector 7 isarranged in the second position II substantially parallel to the beampath A of the antenna 3, electromagnetic waves are not reflected back bythe reflector 7 in the second position II in the direction of theantenna 3, but rather are deflected in the direction of the fillmaterial, and produce a reflection which is detected by the antenna 3 ata point in time which does not correlate with a fill level.

In one implementation of the embodiment illustrated in FIG. 3, thereflector 7 can, in addition to the pivot movement, also be drawn backinto the adjusting device 9, such that it is completely surrounded bythe same and therefore does not generate any reflection ofelectromagnetic waves.

A further embodiment of a security device 5 is illustrated in FIG. 4,wherein the reflector 7 is oriented in the first position Isubstantially perpendicular to the beam path A of the antenna 3, and inthe second position II substantially parallel to this beam path A. Atransitioning from the first position I into the second position II isrealized in the present embodiment by a rotation of the reflector 7which is attached to the adjusting device 9 with a 45° miter joint 19.As in the embodiment according to FIG. 3, the reflector 7 can thereforeeither be arranged in the first position I in a plane which issubstantially perpendicular to the beam path A of the antenna 3, or inthe second position II parallel to the same.

FIG. 5 shows one implementation of the embodiment in FIG. 3, wherein inFIG. 5 the reflector 7 is illustrated in the second position II. In theillustrated embodiment, the reflector 7 is oriented substantiallyparallel to the beam path A of the antenna 3, and is drawn into theguide tube 9 a of the adjusting device 9. In this manner, anyreflections on the reflector 7 are prevented, and at the same time, acontamination of the reflector 7 is prevented as well.

It is hereby noted at this point that a linear movement of the reflector7 is likewise possible between the first position I and the secondposition II.

In all manner of rotary movements, either a continuous movement of thereflector 7 can occur, such that it is possible for a verification ofthe functional capability of the radar-based fill level measurementdevice 1 to be carried out periodically every time the first position Iis reached, or a movement can be initiated upon regular or non-regularrequests by the electronics 13, which can also be initiated manually bya request signal, for example from a measurement station.

LIST OF REFERENCE NUMBERS

-   1 radar-based fill level measurement device-   3 antenna-   4 container-   5 security device-   6 flange-   7 reflector-   9 adjusting device-   9 a protective tube-   9 b miter edge-   9 c passage bearing-   11 drive-   13 electronics-   15 reduction device-   17 axis-   19 miter edge-   A beam path-   I first position-   II second position

The references recited herein are incorporated herein in their entirety,particularly as they relate to teaching the level of ordinary skill inthis art and for any disclosure necessary for the commoner understandingof the subject matter of the claimed invention. It will be clear to aperson of ordinary skill in the art that the above embodiments may bealtered or that insubstantial changes may be made without departing fromthe scope of the invention. Accordingly, the scope of the invention isdetermined by the scope of the following claims and their equitableequivalents.

I claim:
 1. A radar-based fill level measurement device comprising asignal generator for the purpose of generating electromagnetic waves,and an antenna for the purpose of emitting the electromagnetic wavesinto a container, as well as for the purpose of receivingelectromagnetic waves reflected out of the container, further comprisinga security device for the purpose of verifying the functional capabilityor improving the measurement quality of the radar-based fill levelmeasurement device, wherein the security device comprises a reflectorand an adjusting device, and is suitably configured to move thereflector at least between a first position, in which it reflects theelectromagnetic waves, and a second position, in which it reflects theelectromagnetic waves to a reduced degree, wherein the security devicehas a drive which acts on the adjusting device, wherein the drive isconnected to the electronics of the radar-based fill level measurementdevice, and the reflector moves from the second position into the firstposition upon request by the electronics, such that it is possible tocreate an entirely automated process for verifying the properfunctioning of the radar-based fill level measurement device.
 2. Theradar-based fill level measurement device of claim 1, wherein thesecurity device is configured to be spring-loaded in the first position.3. The radar-based fill level measurement device of claim 1, wherein thedrive is driven electrically, electromagnetically, or pneumatically. 4.The radar-based fill level measurement device of claim 1, wherein, inthe second position, a reduction device is arranged in such a mannerthat the reflector is at least partially covered as seen in thedirection of a beam path.
 5. The radar-based fill level measurementdevice of claim 4, wherein the reduction device is configured as adiffusor.
 6. The radar-based fill level measurement device of claim 4,wherein the reduction device is constructed of a material which absorbsthe electromagnetic waves.
 7. The radar-based fill level measurementdevice of claim 4, wherein the reflector in the second position isaccommodated in the reduction device.
 8. The radar-based fill levelmeasurement device of claim 1, wherein the drive is suitably configuredto move the reflector rotationally.
 9. The radar-based fill levelmeasurement device of claim 1, wherein the drive is suitably configuredto move the reflector linearly.
 10. The radar-based fill levelmeasurement device of claim 1, wherein the reflector is arranged in thefirst position substantially perpendicular to a beam path, and in thesecond position substantially parallel to the beam path.
 11. Theradar-based fill level measurement device of claim 1, wherein the driveis suitably controlled to move the reflector continuously andpermanently.